The appearance of cartilage used in deep inferior epigastric perforator breast reconstruction surgery as a calcified mass on CT scan.

This paper describes an unusual radiological appearance of implanted cartilage on CT scan in a patient who had recently undergone deep inferior epigastric perforator (DIEP) breast reconstruction surgery following a mastectomy for ductal carcinoma in situ. The purpose of this paper is to alert medical practitioners involved with DIEP breast reconstruction surgery, as well as general radiologists, to the possibility of surgically implanted costal cartilage undergoing calcification and then appearing on imaging studies as a malignant process. Information on the patient was gathered from clinical records, imaging reports and pathological samples. A literature search was performed to identify similar cases and the results showed that this occurrence has never before been described and therefore represents an advancement of knowledge about the imaging characteristics of reconstructed breast tissue

Low-Temperature Growth of High Resistivity GaAs by Photoassisted Metalorganic Chemical Vapor Deposition

We report the photoassisted low‐temperature (LT) metalorganic chemical vapor deposition (MOCVD) of high resistivity GaAs. The undoped as‐grown GaAs exhibits a resistivity of ∼106 Ω cm, which is the highest reported for undoped material grown in the MOCVD environment. Photoassisted growth of doped and undoped device quality GaAs has been achieved at a substrate temperature of 400 °C in a modified atmospheric pressure MOCVD reactor. By using silane as a dopant gas, the LT photoassisted doped films have high levels of doping and electron mobilities comparable to those achieved by MOCVD for growth temperatures, Tg≳600 °C

Validated Spectrophotometric Methods for the Determination of Nabumetone in Tablets Dosage Form Using Three Dinitrobenzene Reagents

ABSTRACT Three spectrophotometric methods have been described for the determination of nabumetone (NAB) in its tablets dosage form. The methods are based on the reaction of nabumetone with three dinitrobenzene reagents, namely, m-dinitrobenzene (DNB), 1-chloro-2,4-dinitrobenzene (CDNB) and 1-fluoro-2,4-dinitrobenzene (FDNB) in alkaline medium (alcoholic potassium hydroxide solution). The studied reactions depend on the tendency of these dinitrobenzene reagents to react with the active methylene adjacent to the carbonyl group of the drug. Illustrative proposed pathways showing the reaction of NAB with the three dinitrobenzene reagents were presented. Spectrophotometric measurements were achieved by recording the absorbances at 580, 573 and 574 nm for the reaction with DNB, CDNB and FDNB respectively. Different experimental parameters affecting development and stability of the produced colors were optimized. The three methods were validated with respect to linearity, ranges, precision, accuracy and limits of detection and quantification. Beer's law was obeyed in the concentration ranges of 2-10, 40-240 and 10-50 µg/mL for DNB, CDNB and FDNB methods respectively with correlation coefficient values not less than 0.9994. In addition, detection limits of NAB were 0.27, 8.54 and 2.04 µg/mL for DNB, CDNB and FDNB methods, respectively. The proposed methods were successfully applied for assay of the drug in its tablets dosage form. Recovery data obtained by the proposed methods were favorably compared with those obtained by a reported spectrophotometric method

Performance analysis of AlGaAs/GaAs tunnel junctions for ultra-high concentration photovoltaics

An n(++)-GaAs/p(++)-AlGaAs tunnel junction with a peak current density of 10 100Acm(-2) is developed. This device is a tunnel junction for multijunction solar cells, grown lattice-matched on standard GaAs or Ge substrates, with the highest peak current density ever reported. The voltage drop for a current density equivalent to the operation of the multijunction solar cell up to 10 000 suns is below 5 mV. Trap-assisted tunnelling is proposed to be behind this performance, which cannot be justified by simple band-to-band tunnelling. The metal-organic vapour-phase epitaxy growth conditions, which are in the limits of the transport-limited regime, and the heavy tellurium doping levels are the proposed origins of the defects enabling trap-assisted tunnelling. The hypothesis of trap-assisted tunnelling is supported by the observed annealing behaviour of the tunnel junctions, which cannot be explained in terms of dopant diffusion or passivation. For the integration of these tunnel junctions into a triple-junction solar cell, AlGaAs barrier layers are introduced to suppress the formation of parasitic junctions, but this is found to significantly degrade the performance of the tunnel junctions. However, the annealed tunnel junctions with barrier layers still exhibit a peak current density higher than 2500Acm(-2) and a voltage drop at 10 000 suns of around 20 mV, which are excellent properties for tunnel junctions and mean they can serve as low-loss interconnections in multijunction solar cells working at ultra-high concentrations

An integrated approach to unravel the structural controls on groundwater potentialities in hyper-arid regions using satellite and land-based geophysics: a case study in southwestern desert of Egypt

Published versio

Echocardiographic assessment of the tricuspid and pulmonary valves.

Transthoracic echocardiography is the first-line imaging modality in the assessment of right-sided valve disease. The principle objectives of the echocardiographic study are to determine the aetiology, mechanism and severity of valvular dysfunction, as well as consequences on right heart remodelling and estimations of pulmonary artery pressure. Echocardiographic data must be integrated with symptoms, to inform optimal timing and technique of interventions. The most common tricuspid valve abnormality is regurgitation secondary to annular dilatation in the context of atrial fibrillation or left-sided heart disease. Significant pulmonary valve disease is most commonly seen in congenital heart abnormalities. The aetiology and mechanism of tricuspid and pulmonary valve disease can usually be identified by 2-dimensional assessment of leaflet morphology and motion. Colour flow and spectral Doppler are required for assessment of severity, which must integrate data from multiple imaging planes and modalities. Transoesophageal echo is used when transthoracic data is incomplete, although the anterior position of the right heart means that transthoracic imaging is often superior. Three-dimensional echocardiography is a pivotal tool for accurate quantification of right ventricular volumes and regurgitant lesion severity, anatomical characterisation of valve morphology and remodelling pattern, and procedural guidance for catheter-based interventions. Exercise echocardiography may be used to elucidate symptom status and demonstrate functional reserve. CMR and CT should be considered for complimentary data including right ventricular volume quantification, and precise cardiac and extracardiac anatomy. This BSE guideline aims to give practical advice on the standardised acquisition and interpretation of echocardiographic data relating to the pulmonary and tricuspid valves

Fine structure of near-band-edge photoluminescence in He+-irradiated GaN grown on SiC

The effect of He ion implantation on the optical properties of epitaxial GaN-on-SiC was studied. We observed that He + irradiation increases the relative intensity of the “blue emission” and resistivity of GaN films and decreases the intensity of the near-band-edge photoluminescence. Because the intensity of the main peak is drastically decreased, the fine structure of the near-band-edge photoluminescence in GaN after He + irradiation was observed. From a comparison of observed sharp lines with photoluminescence peaks of GaNdoped with oxygen, we conclude that oxygen can produce a complex, which is characterized by a strong localization of free carriers and a large lattice distortion. The zero-phonon line of this defect has energy close to the band-gap energy of GaN